WARNING in map_lookup_elem

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 01fd1694 Linux 4.14.141
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1171ae7a600000
kernel config: https://syzkaller.appspot.com/x/.config?x=62c9b69e1b2adda9
dashboard link: https://syzkaller.appspot.com/bug?extid=925d285ef840673614f7
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10c4b2a2600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1085c582600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+925d28...@syzkaller.appspotmail.com

audit: type=1400 audit(1567098865.343:36): avc: denied { map } for
pid=6865 comm="syz-executor719" path="/root/syz-executor719739499"
dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
IPVS: ftp: loaded support on port[0] = 21
perf buffer not large enough
------------[ cut here ]------------
WARNING: CPU: 0 PID: 6869 at kernel/trace/trace_event_perf.c:273
perf_trace_buf_alloc.cold+0x18/0x2d kernel/trace/trace_event_perf.c:273
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 6869 Comm: syz-executor719 Not tainted 4.14.141 #37
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x138/0x197 lib/dump_stack.c:53
panic+0x1f2/0x426 kernel/panic.c:182
__warn.cold+0x2f/0x36 kernel/panic.c:546
report_bug+0x216/0x254 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x1bb/0x310 arch/x86/kernel/traps.c:295
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:perf_trace_buf_alloc.cold+0x18/0x2d
kernel/trace/trace_event_perf.c:273
RSP: 0018:ffff888081e27bf0 EFLAGS: 00010282
RAX: 000000000000001c RBX: ffff88809e397a80 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffed10103c4f74
RBP: ffff888081e27c18 R08: 000000000000001c R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000033bc
R13: ffff888081e27cb0 R14: ffff888081e27ca0 R15: 0000000000000000
perf_trace_bpf_map_keyval+0x1bc/0x740 include/trace/events/bpf.h:228
trace_bpf_map_lookup_elem include/trace/events/bpf.h:266 [inline]
map_lookup_elem+0x6dd/0xa40 kernel/bpf/syscall.c:513
SYSC_bpf kernel/bpf/syscall.c:1491 [inline]
SyS_bpf+0x5d1/0x2da8 kernel/bpf/syscall.c:1469
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4414b9
RSP: 002b:00007ffd0fc91a48 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004414b9
RDX: 00000000000003a8 RSI: 0000000020c88000 RDI: 0000000000000001
RBP: 0000000000009ee3 R08: 0000000100000000 R09: 0000000100000000
R10: 0000000100000000 R11: 0000000000000246 R12: 0000000000402380
R13: 0000000000402410 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[syzbot]

syzbot suspects this bug was fixed by commit:

commit 95867919494dce594c3c57bbf31247157a881fb7
Author: Paolo Bonzini <pbon...@redhat.com>
Date: Thu Jul 4 09:14:13 2019 +0000

KVM: x86: add tracepoints around __direct_map and FNAME(fetch)

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1721f061e00000
start commit: 01fd1694 Linux 4.14.141
git tree: linux-4.14.y

kernel config: https://syzkaller.appspot.com/x/.config?x=62c9b69e1b2adda9
dashboard link: https://syzkaller.appspot.com/bug?extid=925d285ef840673614f7

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10c4b2a2600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1085c582600000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: KVM: x86: add tracepoints around __direct_map and FNAME(fetch)

For information about bisection process see: https://goo.gl/tpsmEJ#bisection